TW394862B - Lithographic projection apparatus - Google Patents

Abstract

A lithographic projection apparatus comprising: a radiation system for supplying a projection beam of radiation; a mask table provided with a mask holder for holding a mask; a substrate table provided with a substrate holder for holding a substrate; a projection system for imaging an irradiated portion of the mask onto a target portion of the substrate; first driving means, for moving the mask table in a given reference direction substantially parallel to the plane of the table; second driving means, for moving the substrate table parallel to the reference direction so as to be synchronous with the motion of the mask table; the apparatus further comprising: first measuring means, for determining the momentary position of the mask table with respect to a fixed reference point; second measuring means, for determining the momentary position of the substrate table with respect to a fixed reference point, and means for comparing the measured momentary position of the substrate table with a desired momentary position of the substrate table, for generating a position error signal in accordance with a difference between the said two positions, and for passing that signal to correction means which serve to adjust the momentary position of the mask table so as to compensate for such difference. In a preferential embodiment, at least a portion of the position error signal is differentiated twice with respect to time before being passed to the correction means, thus providing the correction means with an acceleration error signal; this can then be used to directly effect the required correctional acceleration of the mask table.

Description

V. Description of the invention (1) The present invention relates to a lithographic projection device, which includes: • an illumination system for supplying a projection Korean beam; • a mask stage 'which is provided with a mask holder to support a mask ; A base table 'which has a base support to support a base; a projection system' which is used to reflect an irradiated portion of the photomask onto the base;

A target part of the body; A • a first driving device for moving the photomask table in a given reference direction substantially parallel to the edge plane; • a second driving device 'for making the base table Move parallel to the reference direction to synchronize with the movement of the mask stage; this type of device can be used, for example, in the manufacture of integrated circuits (ICs). In this case, the 'mask (marking line) may contain a circuit pattern equivalent to the integrated circuit-single / single layer 1, and then this pattern can be reflected on the substrate (silicon that has been coated with a layer of photosensitive material 21 anti-silver agent). Wafer) on the target area (die). Generally speaking, each wafer will contain a complete network of adjacent grains, and these grains will be irradiated one by one. By gradually sweeping the graticule pattern with a given reference inversion 7 (scanning direction) under the projected beam while simultaneously or in parallel or in parallel, scanning the wafer stage in the scanning direction to irradiate each die, thereby Transfer the images of lightly selected m +,,, and line patterns to the die. In general, since the 4-A. Den _ / ^ ^ = system will have an amplification factor M (usually M < 1), the scanning speed of the wafer table: a is a factor M smaller than the scanning speed of the reticle table. . More information on what is described here ~ ίΰι · Dan · / 〇 »can be found in World Patent Application No. WO 97/332 05. Until recently, such devices consisted of a single mask stage and a single substrate stage. all

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I. V. Description of the Invention (2) There are now machines with at least two independent movable base tables. Patent applications Nos. WO 98/28665 and WO 98 / 4〇791. The basic operating principle behind this multilayer device ^ = The multilayer body is positioned below the projection system to give way to the second one of the second § to ~ the base; the new base is sent when the base is exposed; the; : Ran Tong: Fang: Exposure position, and then repeat the cycle here:: 糸, there are machines that can achieve a substantial increase in the cost of machines in this way. With this improvement, the shadow device can use various types of projections, such as an x V ion beam or an electron beam. Projection system = Using :, quasi-reflection, or reflective refraction 1; Π ;: For example, it can be refractive, reflective t ^ ^ < μ # Λ Λ% Λ ^ / ° ^ ^ ^ ^ ^ Of these: = dagger, empty. As described in paragraph 刖, the sundial and / or reticle stage should be installed. The integrated circuit of the device manufacturing and the replicating fish of the sub-micron pattern worn by the device & other devices generally involve very subtle--: i,: (0 "-, mechanical and mechanical impact, etc.): cover: Stray motion systems, airlocks, dynamic balancing weights; for this purpose, the schemes such as this attack will mechanically affect the key parts of the isolation and the most negative. However, these schemes are not intended to exclude certain negative effects.

5. Explanation of the invention (3) It is completely effective, for example: 1. Vibration caused by the mask supporting device (mechanical arm); 2. Marking lines cover the vibration caused by the movement of the blade; 3. Due to air spray The resonance effect caused; 4. Vibration in the base table caused by the movement of the mask table, and vice versa. Although the above effects are relatively small in scale, it will become increasingly important as the demand for higher device resolution increases, and the practical implementation of large-area integrated circuits with critical dimensions of 0.15 microns or less Constitute a substantial obstacle. It is an object of the present invention to alleviate this problem. More specifically, it is an object of the present invention to provide a step-and-scan lithographic projection device in which the aforementioned disturbance effect is reduced. More specifically, it is an object of the present invention that the device should include an asynchronous movement between the base table and the photomask table that counteracts such disturbances. The above and other objectives are achieved in the device described in the previous paragraph. The features of the device also include:-a first measuring device, which is used to determine the instantaneous position of the mask stage relative to a fixed reference point;-a second measuring device , Which is used to determine the instantaneous position of the base table relative to a fixed reference point; and-a device for comparing the measured instantaneous position of the base table with the desired instantaneous position (set point) of the base table, which is generated based on the difference between the two positions A position error signal is sent to the correction device, and the correction device adjusts the instantaneous position of the mask stage to compensate the error.

V. Description of the invention (4) After a deep understanding of the present invention, it is found that the aforementioned disturbances can not be removed by structural modification of the lithography device. The only practical solution is to use Control Theory as the basis. The scheme. In the experiments before the invention, the inventor tried to use the second measuring device to quantify the grammatical error in the base-body table (by comparing the measured position and expected position of the base table) and used a feedback connected to the second driving device The loop repeatedly removes this error to correct it. However, although this scheme has improved to some extent, it cannot remove all negative disturbances; further analysis shows that using this processing scheme does not meet the requirements to reduce the characteristic frequency of about 200 Hz, but at low frequencies (such as (20 to 80 Hz) does show a reduction of the former in the present invention, which is negative to the photomask, but it is completely rectified by body disturbance regardless of the case. Attempting to use this method in the face-to-face disturbance effect idea The structure is generally higher than that of the base body, and the characteristics of the tiger will be higher than the latter when the frequency is about 200 Hz. How, the inventor's eye magnification 1 (usually m = i / 4 sees the amount of disturbance of the mask stage will greatly eliminate the negative disturbance, it is better to compensate for any residual. The disturbance, the experiment in this case produces excellent results. According to the device of the present invention — Special people in the new solution to this problem abandoned the attempt to completely remove the substrate and shifted the attention to the mask stage. The stage is not complicated and lightweight, and it is expected to be simple. Experiments have proven that this assumption is inside the real mask stage The amplitude of the perturbation is generally turned to the next problem, because the photomask or 175) is projected on the substrate, which is reduced from the base amplitude. Rather than trying to tune the base table as an option, the invention is conceived. Then, in the embodiment, the first measurement can be used. 5. Description of the invention (5) ----^ Quantize the position error of the mask stage (by comparing the measurement position and the position of the mask stage) and use A feedback loop connected to the first driving device repeatedly mitigates such errors to overcome such errors. = The defective embodiment discussed in the paragraph can be established because of this, depending on the light reflection, the bandwidth of the loop is usually about 150 to 175 Hz, which is lower than the characteristic frequency range of 175 to 225 Hz for the most persistent disturbances. Therefore, the input of the feedback loop of the moving right hood provides the disturbance data in the post-frequency range; the method can perfectly overcome this disturbance. In order to avoid this problem, according to a preferred implementation of the device of the present invention, the error signal is sent to the correction device, and a part of the position correction device provides an acceleration error. '4 Differential twice, so that the first drive device is not supplied to the light. After 2 this signal can be directly fed by multiplying the acceleration error to the light army platform :: the input of the road; we borrow the power required by the position . Here I immediately learned that the correction mask stage, according to another embodiment of the device of the present invention, is ## sent via a lead_lag filter ', V — part of the position error is used to compensate any fixed Device, the filter ensures that the compensation produced by the adjustment of the mask stage is non-existent (delayed). This solution is so accurate that the image positioning of the device is accurate. The original servo in the base station after the second team should be based on the content discussed in the previous paragraph. The error signal is also sent to the correction device. Occurrence of low negative system lag In a special improvement of one of the foregoing embodiments, it was adjusted to produce the best within the spectrum portion of the lead-lag filter field where the position error has the most. 5. Description of the Invention (6) Efficiency. In a particular example, the filter is implemented to have optimal performance in the range of 75 to 225 Hz. In another embodiment of the device according to the present invention, a second measuring device (comparing the measured position and the expected position of the base table) is used to quantify the position error of the base table, and a feedback loop connected to the second drive device is used to mitigate this repeatedly. Kind of hindrance. This solution works in tandem with the basic inventive method to help reduce the uncomfortable pain of the relative positions of the photomask table and the base table. '' In the foregoing, the desired instantaneous position (set point) of the base table and / or the mask table can be obtained, for example, by a (software) set point generator, which sets / desired synchronized movements of the two sets Generate a (mathematical) graph. Here, the fixed reference point of the I solution relative to the measured position of the base table and the fixed reference point of the measured position of the cover table may be the same or different. Depending on the choice, 疋 ° —ίΓ ”about a device manufacturing method, It includes the following steps: ^. The soil body, the substrate is at least partially covered by a layer of radiation-sensitive material, a photomask, the photomask contains a pattern; providing a household beam to project and image at least part of the photomask pattern on the layer軚 Shoot the sensible material—on the target area. According to the present invention, the method is characterized by: _ δ mysterious mask is supported by an apricot, so that the mask stage is connected to the first mask stage from one level to two. Drive device-the base is supported on a base to move in a given reference direction; set the base table-parallel "reference; connected to a second drive device to move with the mask stage

Page 12 1 V. Explanation of the invention (7) Motion synchronization;-Use the first measurement device to determine the instantaneous position of the photomask stage; At the fixed reference point-= Use the Hth device to determine the instantaneous position of the base table ^ Can be clicked-use a device to compare the instantaneous position of the base table after measurement, and generate it based on the difference between the two positions-仂 1 1 For the instantaneous position error signal, say that the signal is sent to adjust the mask table Instantaneous position, error. The τ1 device is compensated for the pattern in a photolithographic projection device according to the present invention. The pattern is reflected on a substrate, and the substrate is covered by a sensitive material (resist). Prior to this mapping step, the substrate is subjected to various treatments, such as priming, resist coating, and soft baking (s 0 f t b a k e). The substrate may undergo other treatments after exposure, such as post-exposure bake (PEB), imaging, hard bake, and pattern measurement / inspection after imaging. This series of processes serves as the basis for patterning the individual layers of a device, such as an integrated circuit. Then, the patterned layer is subjected to various processes, such as etching, ion implantation (doping), metallization, oxidation, chemical mechanical polishing, etc. All of the procedures need to grind a separate layer. If several layers are required, the entire program or its variation must be repeated for each new layer. Finally, a series of devices appear on the substrate (wafer). These devices are then separated by pelletizing or dividing saws. ′ Individual devices can then be mounted on a carrier or connected pins, etc. More information on this process can be found, for example, in McGraw Hi u Publishing

Page 13 V. Description of Invention (8) Book "Microchip Fabrication: A Practical Guide to Semiconductor Processing" by Peter van Zani: 'The third edition of 1997, ISBN 0-0 7-067250-4 Although the use of the device according to the present invention in the fabrication of integrated circuits has been described above, it should be understood that this device has many other possible uses. For example, 'it can be used to integrate optical systems, magnetic memory, etc. In the manufacture of guidance and detection patterns, liquid crystal display panels, thin-film magnetic heads, etc. Those skilled in this art will understand that in the connotation of these other uses, the words used in this article, such as,, marking, / ,, , Wafer, or chip should be considered to be replaced with more general terms, mask, substrate, and, and target areas, respectively. The following is an example embodiment and a diagram. The formula further illustrates the invention and its advantages. In the figure: Figure 1 is a simplified reproduction of a control circuit suitable for a device according to the invention; Figure 2 shows a photomask in a special embodiment of the device according to the invention Taiwan and Ji Station frequency response; Figure 3 outlines a general diagram of the device according to the present invention. F The corresponding parts in the figure are represented by the same reference symbols. The figure shows the special embodiment of the correction circuit used in the device according to the present invention. Table (or marking table: RS), including mechanical wheel parts $ ^ control part GRS. The bottom circuit represents the base table (or wafer table: WS), including the transmission part H * S and control part Gws. To four times the wafer table setting "'P', but its output only calculates 1/4 of the relevant WS / RS error.

V. Description of the invention (9) " "--Except a low-pass filter HF (plus -4) feeds the WS error effS to the set point SPR of the RS. The double differentiator D generates a WS acceleration error. By accelerating this, the RS mass (m) will generate an extra force. When this force is applied to the marked line *, the RS should have the same acceleration as ws. & It may also contain a super-J-hysteresis component to optimize the feedthrough in a specific frequency range. This gas component is further explained in the second embodiment a. When the disturbance is weak. Resolved. What is the reason for this RS? Even if it is in the desired state of RS, there is a slight wave; gain, when the embodiment is caused by a relatively strong force applied to the RS control itself, it will consider this force to be a η ', η reacts to this response and plots the feedforward (fe, e ^ f 〇rwar ^) effect by subtracting the ws error after additional filtering on the RS setpoint feed. This problem can be solved, in 'If RS reacts to this additional feedforward force For a transmission of 1 / ms2, the error eRS is kept at zero and therefore the RS controller does not notice the "injection of power". The main advantage of the feed 彳 § $ form is that it has nothing to do with the bandwidth of RS. Ready, it ’s common to see that this extra force halo feedforward produces the desired RS response. Only when the dynamic response deviates from the ideal model 1 / ms2 will the response of the RS become irrational. ○ Note that for practical purposes, the real wave filter structure can be chosen the same. For example, ‘two filters with the same denominator polymorphism can be used. In the case of f’, only the numerator is different, and the low-pass filter has only one. The high-pass filter has m · s2 terms. When using the feed signal method shown in Figure 1, the main cause of the residual WS / RS error is the phase difference of the South frequency. This phase lag is due to the road from self-shock to RS

Page 15 V. Description of the invention (10) The remaining hysteresis in the radius causes the spectrum of the WS position error (the spectrum of the top line (,!), The right one is ruled + IT, Y 0, see 1 #is divided ' The M Sibei " σ is below the top line), and the net error spectrum of the WS level (bottom 鎞, orthogonal directions X (top) and γ (bottom)) define s., Y νλ directions. Pi bismuth Also, „, & y, 疋, 仏, Y, Y, and Y, where Y is the scan multiplied by i.-. As shown in the figure, the number of R: f straight up must follow WS. Especially in low-frequency sun: it is quite Exact difference. However, for m = 225 Hz, == = works well in amplitude, but residual errors; = is particularly obvious inward with ΐΐκΙΓΛ. This increase in net error is due to ws errors. Phase difference between RS responses. 'W 6 Reduces phase error by adding a lead-lag filter. After performing various optimization cycles, the net low)' has a zero frequency at 175 Hz and a frequency of 2.5 Hertz has-2 li: frequency). Τ upper collar (the table of pole J lists the net WS / RS error stolen obtained by using this filter), and the use of Figure 1 The results obtained by the scheme (,, / / / skin and unprocessed results (,, uncorrected) obtained without applying the present invention. MA and MSD are moving average and moving standard deviation, respectively. 仃) denier The ratio units are all nanometers, and the χ and γ directions mentioned in the previous paragraph are cited. The uncorrected loop filter MA X 11.4 1.4 1.0 MSD X 1 4. 9 7. 9 6.9

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V. Description of the invention (11) MAY MSD Y 4. 322. 1. 6 15. 1. 9. Embodiment 3 FIG. 3 outlines a schematic perspective view of a lithographic projection device according to the present invention. The device comprises: an illumination system 7 for supplying a projection radiation beam 33 (such as ultraviolet, far ultraviolet, X-ray or charged particle beams); a photomask stage 5 having a photomask holder 27 to support a photomask 29 (Such as a graticule).

-Substrate table 1, which includes-Substrate support M7 to support a resist-coated silicon wafer); M i V bands are mirrored by the inner beam 33 of the projection mask and the tape-projection system 3Γ For example-a lens or a refracting system, a mirror surface, or a 5 Ϊ Γ f system), which is used to irradiate the reticle 29-the irradiated portion A, the target portion 3 5 of one of the substrates 19 ( Die); as described herein, the device is a transmissive system. However, the device also contains a transmissive mask and / or a projection system. For reflection ', for example, equipped with-the reflective radiation system 7 contains a light source 9 [for example, a mercury lamp or a particle source (such as a thermionic cathode), a file laser, a ripple provided by the electron beam path # f = enclosure storage or synchronous acceleration . The radiation beam 33 is generated by each of the illuminating bodies 13 and 13-the radiant excited Korean beam 25 is approximately collimated in cross section so that the system 7 intercepts a marking 29 that supports the branch 27. With the first driving device 31 +

Page 17 V. Description of the invention (12) / σΥ direction (known as the scanning direction) moves back and forth accurately. After passing the marking line 29, it passes through the -projection system 3, which will radiate n, on the die 35 of the wafer 19. With the body of the second driving device 21: Second, the base edge 1 can also go back and forth accurately in the γ * direction (scanning * direction). 2 W also moves back and forth in the X direction, and additionally has other substrates. During scanning, the reticle 5 scans at a speed v:. The projected beam sweeps through the graticule image. Here, the substrate ^ moves 让 to move in the same or opposite direction, where M is cast = / 迷 度 4 or 丨 川. In this way let larger crystals = Λ through η sacrifice resolution. It is not necessary to bring it to the first place. ^ This invention is used to help ensure that the mask stage does exactly the same as the scanning movement described in the first embodiment. Matrix phase r 1 can be

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Claims (1)

_Case No. 88109912_ I am revised,:; Ή.Ί 6. Scope of patent application 1. A lithographic projection device comprising: • an illumination system for supplying a projection radiation beam; • a mask stage It has a photomask support to support a photomask; • a base table that has a base support to support a substrate; • a projection system for reflecting an irradiated part of the photomask on the substrate A target part; • a first driving device for moving the photomask table in a given reference direction substantially parallel to the plane of the table; • a second driving device for making the base table parallel to the The reference direction moves to synchronize with the movement of the mask stage; it is characterized in that the device further comprises:-a first measuring device for determining the instantaneous position of the mask stage relative to a fixed reference point;-a second measuring device , Which is used to determine the instantaneous position of the base table relative to a fixed reference point; and-a device that compares the measured instantaneous position of the base table with the desired instantaneous position of the base table, and generates a based on the difference between the two positions Position error signal and the signal supplied to the correcting means, the correction means for adjusting the instantaneous position of the reticle stage to compensate for the error. 2. The device according to item 1 of the patent application is characterized in that at least a part of the position error signal is differentiated twice before being sent to the correction device, thereby providing an acceleration error signal to the correction device. 3. For the device in the scope of patent application, the characteristic is that at least part of the position error signal is sent to the correction device through a lead-lag filter. O: \ 58 \ 58908.ptc Page 1 2000.04.01.019 _Case No. 88109912_ year i correction,:; Ή.Ί VI. Patent application scope 1. A lithographic projection device, which includes: • an illumination system For supplying a projection radiation beam; • a photomask table provided with a photomask support to support a photomask; • a base table provided with a base support to support a substrate; • a projection system used for An irradiated part of the photomask is reflected on a target part of the substrate; a first driving device for moving the photomask table in a given reference direction substantially parallel to a plane of the table; 2 driving devices for moving the base table parallel to the reference direction to synchronize with the movement of the photomask table; characterized in that the device also includes:-a first measuring device for determining the photomask table relative to Instantaneous position at a fixed reference point;-a second measuring device for determining the instantaneous position of the base table relative to a fixed reference point; and-a device for comparing the instantaneous position of the measured base table with the instantaneous position of the desired base table ,its Thus the difference between the two positions to produce a position error signal and the signal supplied to the correcting means, the correction means for adjusting the instantaneous position of the reticle stage to compensate for the error. 2. The device according to item 1 of the patent application is characterized in that at least a part of the position error signal is differentiated twice before being sent to the correction device, thereby providing an acceleration error signal to the correction device. 3. For the device in the scope of patent application, the characteristic is that at least part of the position error signal is sent to the correction device through a lead-lag filter. O: \ 58 \ 58908.ptc Page 1 2000.04.01.019 Case No. 8810 卯 1? 6. The scope of the patent application is set, and the filter is used to compensate for the compensation. · If the third scope of the patent application scope is adjusted to the error information at this position Health best performance. 5. If the scope of patent application No. 3 is adjusted to 175 to 225 Hz 6. If the scope of patent application No. 1 lies in that the device contains a first-ratio measurement of any difference between the instantaneous position of the photomask stage and the position of the household weight—drive Device to adjust the mask connection 7 · If the scope of the patent application is that the device contains a second ratio to measure any difference between the instantaneous position of the base table and the position of the household weight — drive the device to adjust the base disturbance 8. If applied The scope of the patent is that the position error signal passes through 9. A device manufacturing method-k is provided for a substrate, the substrate is covered;-a photomask is provided, which uses a radiation projection beam to layer one of the layers to radiation-sensitive materials Any inherent time inertia within the device. The device of the term is characterized in that the device of the term whose filter number has the largest amplitude in the spectrum portion is characterized in that it produces the best performance in the frequency range of the wave filter. The device according to any one of items 5 to 5, characterized in that the first comparator is used to compare a desired instantaneous position, which is based on the second "signal" of the photomask stage and sends the signal to the instantaneous position of the first-and borrows This reduces the difference. The device according to any one of items 5 to 5, which has a characteristic comparator, and the second comparator is used to compare the desired instantaneous position, which is based on the two second signals of the base table and sends the signal to the second instantaneous position and thereby Reduce this difference. ^ 5. The device of any one of the items, characterized in that an optical fiber link is sent to the correction device. , Which includes the following steps: to>, a layer partially exposed to radiation-sensitive material contains a pattern; at least part of the mask pattern is projected and imaged on the target area. O: \ 58 \ 58908.ptc $ 2 pages 2000. 04. 01. 〇2〇_Case No. 88109912_Amendment of the year of the year_ 'Patent application scope is characterized by:-The photomask is supported on a photomask table, the photomask table is connected to The first driving device moves the photomask table in a given reference direction parallel to the plane of the table-the base is supported on a base table, the base table is connected to the second driving device so that the base table is parallel to the reference Directional movement so as to synchronize with the movement of the photomask table;-the first measurement device is used to determine the instantaneous position of the photomask table relative to a fixed reference point;-the second measurement device is used to determine the base table relative to a fixed reference point Instantaneous position;-using a device to compare the instantaneous position of the base table after measurement with the desired instantaneous position, generate a position error signal based on the difference between the two positions, and send the signal to adjust the instantaneous position of the photomask table The device is corrected to compensate for this error. 10. A device manufactured in accordance with the method of item 9 of the scope of patent application O: \ 58 \ 58908.ptc Page 3 2000. 04.01.021